Drinking five or more cups of coffee a day increases the risk of having heart problems 2.8 times, according to researchers at the Johns Hopkins Medical Institutions in Baltimore. After correcting for other factors  such as age, smoking habits and hypertenstion  they found heavy coffee drinkers still have 2.5 times the incidence of coronary heart disease compared with nondrinkers. Those who drank a moderate amount (from two to four cups a day) had a twofold risk of heart disease.

Scientists suspected that any adverse effect must trace to caffeine. However, a study by H. Robert Superko of the University of California's Center for Progressive Atherosclerosis Management in Berkeley reported that decaffeinated coffee  but no regular  may nudge cholesterol levels in the direction of increased heart risk. The 16-week study involved 181 healthy, nonsmoking men who routinely drank three to six cups of coffee per day. The researchers provided all volunteers with regular, drip-grind coffee and instructed them on how to brew it. Eight weeks later, they randomly assigned each man to one of three regimens: the same coffee, a switch to decaf, or abstinence from coffee. Participants were asked to avoid other caffeine sources throughout the study.

Those who drank regular coffee and those who abstained showed no changes in blood cholesterol levels during the study, the team reported in the American Journal of Clinical Nutrition. The decaf group, however, experienced a roughly 6 percent increase in low-density lipoprotein (LDL) cholesterol, the so-called bad cholesterol linked to heart attacks.

A meta-analysis by Martin G. Myers, M.D., University of Toronto and colleagues from other institutions, involving 11 published studies, was published in the Archives of Internal Medicine. These studies lasted from two to 35 years and followed people who initially had no evidence of heart disease. Only three of the studies found that increased rates of coffee drinking are associated with the development of heart disease. Most (eight) found no evidence of an association at all. The authors concluded that people who consumed up to one cup of coffee daily had the same incidence of heart disease as those who consumed more than six cups a day.